So much of what happens in our lives — good, bad and otherwise — happens because of timing.

We see it in sports. Throwing the ball a second too early or too late can turn a game-changing touchdown pass into a near-miss incompletion.

We hear it in comedy. A punchline delivered at the wrong time can ruin even an impeccably written joke.

We see it over and over again in love, too — and not just in the movies. I met my wife through a fluke of timing. We both arrived unusually early for a class while we were students at the University of Texas. While we were waiting for the doors to open so we could enter the classroom, I sat down next to her and introduced myself. The rest is history, but none of it might have happened if I had arrived just a few minutes later to that class.

Timing is also crucial when it comes to money. Balance transfers are a perfect example.

Let me explain …

Credit card balance transfers are appealing because they give you the chance to shift your balance to a lower APR and save yourself a whole lot of interest payments in the process.

The savings can be huge — in the thousands of dollars, potentially — and the biggest savings come from cards that offer a 0 percent interest rate for a short period of time, typically anywhere between six and 18 months. Sure, these transfers come with other costs (balance transfer fees and annual fees), but the amount you save in interest can often dwarf the cost of those fees, so it is still often a good deal for the cardholder.

However, if your timing is off, that can all change — and what looks like a good deal can turn into a money pit.

Here’s why:

1. The 0 percent balance transfer APR is a limited-time offer. That 0 percent APR won’t last forever. If you can pay your transferred balance off during that window, you’re in great shape. If you can’t, you might find yourself paying an APR as high as 24.99 percent on the balance that’s left once the introductory rate ends. That can mean big trouble, so be sure to know what your card’s standard APR will be before you get it.

2. The introductory rate can be taken away easily. “We may end your introductory APR and apply the penalty APR if you make a late payment.” Language like this is found in the terms and conditions of many balance transfer cards, and it’s extremely important. Essentially, if you’re late with a payment — not 30 or 60 days late, just late — the issuer can replace your sweet 0 percent deal with a sky-high “penalty” interest rate. Those typically run near 30 percent and can quickly turn your credit card debt problem into a major crisis.

3. A balance transfer can wipe out the grace period on other purchases. A credit card’s grace period can be a beautiful thing. Pay your entire balance off within that window and you won’t pay a cent of interest on what you bought. However, roll a balance over from month to month — even a transferred balance — and that grace period vanishes. That means unless you pay your balance transfer off in the first billing period, every new purchase you make with that card will start accruing interest immediately. It might not seem like a big deal, especially if you limit the amount of new purchases you make on the card. However, as anyone who has suffered with credit card debt can tell you, interest can snowball quickly, and that’s the last thing you want to happen when you’re trying to pay down your debt.

So while balance transfers may not be as romantic as the story of a couple’s first meeting or as dramatic as a perfectly timed and thrown touchdown pass, they can make a real difference to your finances. If you miss deadlines or make mistakes, they can come back and bite you in the wallet. But if you play by the rules and do all the little things right, they can save you thousands — and that’s a happy ending that anyone can love.

More from U.S. News

8 Ways to Maximize Your Credit Card Rewards

10 Ways Consumers Are Often Duped

Should You Invest or Pay Off Debt?

3 Reasons Your Balance Transfer Can Turn From a Deal to Disaster originally appeared on usnews.com